Abstract

The two‐photon fluorescence technique has been used to examine, on a picosecond time scale, the output of a long‐pulse (non‐Q‐switched) Nd:glass laser. The well‐known ``spikes,'' about 200 nsec wide, are found, in many cases, to consist of a large number of ultrashort pulses, about 3 psec in duration. In a non‐Q‐switched ruby laser, pulses about 15 psec in duration have been seen.